共查询到20条相似文献,搜索用时 15 毫秒
1.
É. I. Isaev A. I. Likhtenshtein Yu. Kh. Vekilov E. A. Smirnova 《Physics of the Solid State》2004,46(7):1188-1194
Phonon spectra and phonon density of states of intermetallic compounds Ni3Al and NiAl are studied using the ab initio linear-response method. The calculated phonon dispersion curves agree well with the inelastic neutron scattering data available for the crystals under study. 相似文献
2.
In this paper we report the results obtained from inelastic neutron scattering measurements on Zr2NiH1.9 and Zr2NiH4.6 using triple-axis spectrometer at Dhruva reactor, Trombay. The spectrum up to 35 meV represents largely the lattice modes
of Zr and Ni atoms. The vibrational frequencies of hydrogen atoms are expected predominantly at higher energies. The phonon
spectra from 35–180 meV were recorded using a Be filter as analyser. In order to analyse the observed neutron spectra, we
assume a set of Ein-stein modes due to the hydrogen atoms which are delta functions in energy. These delta functions are broadened
by the resolution of the instrument. The vibrational frequencies obtained from the fitting of the observed phonon spectra
have been assigned to various tetrahedral sites in both the compounds. 相似文献
3.
The spectra of electron paramagnetic resonance and inelastic neutron scattering in crystals of the heavy-fermion intermetallic compound YbRh2Si2 are interpreted. The phenomenological potentials of the crystal electric field of Yb3+ tetragonal centers and the parameter of the Hamiltonian for the spin-orbit interaction of electrons are determined from the experimental energy level schemes. A comparison of the results obtained from experimental data on electron paramagnetic resonance, inelastic neutron scattering, and Mössbauer spectroscopy shows that the most probable ground state of Yb3+ ions in the YbRh2Si2 crystal is the Kramers doublet Γ t6 ? . 相似文献
4.
A. V. Knotko A. V. Garshev M. N. Pulkin V. I. Putlyaev S. I. Morozov 《Physics of the Solid State》2004,46(3):424-429
The oxidation kinetics of Bi1.3Pb0.8Sr2Ca0.8Y0.2Cu2O8+δ solid solutions at different temperatures and \(p_{O_2 } = 0.21\) atm is investigated by thermogravimetry. The results obtained are compared with the previously studied oxidation kinetics of Bi1.3Pb0.8Sr2Ca0.8Y0.2Cu2O8+δ solid solutions. It is found that the substitution of yttrium for calcium leads to an appreciable retardation of the initial oxidation stage associated with the oxygen diffusion. The phonon spectra of the solid solutions are examined using inelastic neutron scattering on a DIN-2PI direct-geometry spectrometer. The high-frequency (>50 meV) phonon densities of states for yttrium-containing and yttrium-free solid solutions are analyzed. The possible model is proposed for a correlation between the differences observed in the high-frequency phonon densities of states attributed to the vibrations of oxygen atoms and the differences in the oxidation kinetics of the solid solutions under consideration. 相似文献
5.
NaNbO3 and (Sr,Ca)TiO3 exhibit an unusual complex sequence of temperature- and pressure-driven structural phase transitions. We have carried out
lattice dynamical studies to understand the phonon modes responsible for these phase transitions. Inelastic neutron scattering
measurements using powder samples were carried out at the Dhruva reactor, which provide the phonon density of states. Lattice
dynamical models have been developed for SrTiO3 and CaTiO3 which have been fruitfully employed to study the phonon spectra and vibrational properties of the solid solution (Sr,Ca)TiO3.
相似文献
6.
G. F. Syrykh N. V. Situkha N. A. Klimenko J. A. Stride 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(3):409-411
A high-resolution (1.5 meV) inelastic neutron scattering experiment is carried out to investigate in detail the low momentum (0.6–1.5 Å?1) dynamic response in Zr50Be50 metallic glass. The results are obtained on the hot neutron three-axis spectrometer IN1 in the Laue-Langevin Institute (Grenoble, France). A comparison with recent neutron scattering results for the momentum transfer region above 1.4 Å?1 shows a minimum in the dispersion relation of low energy excitations near the prepeak of the static structure factor. These excitations appear to be due to the short-range order in this amorphous system. 相似文献
7.
V. A. Stefanovich L. M. Suslikov Z. P. Gad’mashi E. Yu. Peresh V. I. Sidei O. V. Zubaka I. V. Galagovets 《Physics of the Solid State》2004,46(6):1024-1026
Raman scattering in Rb2TeBr6 and Cs2TeBr6 crystals is studied. The phonon spectra of the crystals are calculated using the factor group method. The number of Raman-active modes, their symmetries, and selection rules are found. Observed Raman spectrum lines are identified with atomic vibration modes of the crystal. 相似文献
8.
9.
A. V. Rybina K. S. Nemkovski V. B. Filippov A. V. Dukhnenko 《Physics of the Solid State》2010,52(5):894-898
The first results of measuring dispersion curves of acoustic phonons in the ZrB12 superconductor are reported. The measurements have been conducted by the inelastic neutron scattering method on an ATOS three-axis
spectrometer (IR-8, Russian Research Centre “Kurchatov Institute,” Moscow) at room temperature with a single crystal grown
using a 99.5%-enriched 11B isotope. The results obtained have been analyzed in terms of the lattice dynamics model proposed earlier for rare-earth
dodecaborides. In this model, the constants of the force interaction of Zr atoms with one another and with the boron framework
have been determined. 相似文献
10.
B. Klobes Y. Arinicheva S. Neumeier R. E. Simon A. Jafari D. Bosbach R. P. Hermann 《Hyperfine Interactions》2016,237(1):31
Hyperfine interactions in europium orthophosphate EuPO4 were investigated using 151Eu Mössbauer spectroscopy from 6 to 300 K. The value of the quadrupole splitting and the asymmetry parameter were refined and further substantiated by nuclear forward scattering data obtained at room temperature. The temperature dependence of the relative absorption was modeled with an Eu specific Debye temperature of 221(1) K. Eu partial lattice dynamics were probed by means of nuclear inelastic scattering and the mean force constant, the Lamb-Mössbauer factor, the internal energy, the vibrational entropy, the average phonon group velocity were calculated using the extracted density of phonon states. In general, Eu specific vibrations are characterized by rather small phonon energies and contribute strongly to the total entropy of the system. Although there is no classical Debye like behavior at low vibrational energies, the average phonon group velocity can be reasonably approximated using a linear fit. 相似文献
11.
12.
E. Farhi A.K. Tagantsev R. Currat B. Hehlen E. Courtens L.A. Boatner 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(4):615-623
High resolution data on low energy phonon branches (acoustic and soft optic) along the three principal symmetry axes in pure
KTaO3 were obtained by cold neutron inelastic scattering between 10 and 80 K. Additional off-principal axis measurements were performed
to characterize the dispersion anisotropy (away from the and axes). The parameters of the phenomenological model proposed by Vaks [28] are refined in order to successfully describe the
experimental low temperature (10 <
T
< 100 K) dispersion curves, over an appreciable reciprocal space volume around the zone center ( rlu). The refined model, which involves only 4 temperature-independent adjustable parameters, is intended to serve as a basis
for quantitative computations of multiphonon processes.
Received: 29 September 1999 and Received in final form 6 January 2000 相似文献
13.
S. N. Gvasaliya B. Roessli R. A. Cowley S. G. Lushnikov A. Choubey P. Günter 《JETP Letters》2004,80(5):355-358
The low-energy part of the vibration spectrum of KNbO3 was studied by cold neutron inelastic scattering in the cubic phase. In addition to acoustic phonons, we observe strong diffuse scattering, which consists of two components. The first one is quasistatic and has a temperature-independent intensity. The second component appears as quasielastic scattering in the neutron spectrum, indicating a dynamic origin. From analysis of the inelastic data, we conclude that the quasielastic component and the acoustic phonon are mutually coupled. The susceptibility associated with the quasielastic component grows as the temperature approaches T C . 相似文献
14.
Coupled-channels calculations for the elastic and inelastic scattering of K+ at 715 MeV/c by 6Li and 12C at 635, 715 and 800 kaon Lab momenta have been analysed. The optical potentials of 12C and 6Li are calculated in terms of the alpha-particle and deuteron optical potentials. Good fits to the experimental data and phenomenological
calculations are obtained for 6Li and 12C nuclei. 相似文献
15.
G. E. Abrosimova A. S. Aronin N. S. Afonikova N. P. Kobelev 《Physics of the Solid State》2010,52(9):1892-1898
The influence of plastic deformation on the structure of the Pd40Ni40P20 amorphous alloy has been investigated using X-ray diffraction and measurements of the velocity of sound. It has been revealed
that the rolling of the sample leads to a change in the structure of the amorphous phase (distortion of the first coordination
sphere) and that the structural transformations are more pronounced in the near-surface region of the sample. The rolling
also results in a decrease in the transverse velocity of sound. The observed effects decrease with time. It has been demonstrated
that the revealed effects are associated with the inelastic deformation of the amorphous alloy. 相似文献
16.
L. Pintschovius F. Weber W. Reichardt A. Kreyssig R. Heid D. Reznik O. Stockert K. Hradil 《Pramana》2008,71(4):687-693
Phonons in a metal interact with conduction electrons which give rise to a finite linewidth. In the normal state, this leads
to a Lorentzian shape of the phonon line. Density functional theory is able to predict the phonon linewidths as a function
of wave vector for each branch of the phonon dispersion. An experimental verification of such predictions is feasible only
for compounds with very strong electron-phonon coupling. YN2B2C was chosen as a test example because it is a conventional superconductor with a fairly high T
c (15.2 K). Inelastic neutron scattering experiments did largely confirm the theoretical predictions. Moreover, they revealed
a strong temperature dependence of the linewidths of some phonons with particularly strong electron-phonon coupling which
can as yet only qualitatively be accounted for by theory. For such phonons, marked changes of the phonon frequencies and linewidths
were observed from room temperature down to 15 K. Further changes were observed on entering into the superconducting state.
These changes can, however, not be described simply by a change of the phonon linewidth.
相似文献
17.
Magnetic excitations in the antiferromagnetic Bi2CuO4 (T N =42K) are investigated on the basis of anisotropic exchange interaction between spins of Cu2+ ions. We calculate the dispersion curves and evaluate the intensity of the inelastic neutron scattering by spin wave excitations. Spin contraction at OK and the effect of spin wave interaction are studied. 相似文献
18.
In this paper the phonon dispersion for the bcc metals Mo and Cr is calculated based on the pair potentials obtained from cohesive energies and the Slater-Kirkwood- type three body interaction. In the calculation of the pair potentials the Möbius transform in the number theory is used and the cohesive energy is evaluated by the LMTO method. The results show a good agreement with inelastic neutron scattering data and indicate that the three-body interaction is necessary to account for the phonon dispersion. 相似文献
19.
20.
L. S. Smirnov I. Natkaniec A. S. Ivanov A. Pawlukojc S. I. Troyanov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(6):982-986
The vibrational modes of hydrogen bonds in CsH5(PO4)2 and NaH5P2O6 compounds are analyzed via inelastic incoherent neutron scattering in a wide range of temperatures and Raman light scattering at room temperature. The energy ranges have been determined for the γ, jg, and ? bands of the vibrational modes of acid hydrogens of these compounds. The dependences of the energy on the length of hydrogen bonds in CsH5(PO4)2 have been revealed. 相似文献